What is the purpose of the felt-tip pen during propeller removal?

What is the purpose of the felt-tip pen during propeller removal?

• A. To mark alignment between the propeller hub and the engine flange.
• B. To sign the maintenance log.
• C. To label tools used.
• D. To record vibration data.

Answer: (A)

Indexing the propeller to the engine is the main idea here. The felt-tip pen is used to create alignment marks on the mating surfaces—the propeller hub and the engine flange—so you can reinstall the propeller in exactly the same orientation. This ensures the hub lines up with the flange (and any dowel pins or keyways), preserving balance and proper fit. If you swap orientations, you can introduce vibration or imbalance and risk improper seating of bolts or interference with parts nearby. Those marks are not for signing logs, labeling tools, or recording data; they simply provide a visual reference for correct reassembly.

Indexing the propeller to the engine is the main idea here. The felt-tip pen is used to create alignment marks on the mating surfaces—the propeller hub and the engine flange—so you can reinstall the propeller in exactly the same orientation. This ensures the hub lines up with the flange (and any dowel pins or keyways), preserving balance and proper fit. If you swap orientations, you can introduce vibration or imbalance and risk improper seating of bolts or interference with parts nearby. Those marks are not for signing logs, labeling tools, or recording data; they simply provide a visual reference for correct reassembly.